noun

something pledged as security for repayment of a loan, to be forfeited in the event of a default.

she put her house up as collateral for the bank loan

security,surety,guarantee,guaranty,pledge,bond,insurance,indemnity,indemnification,pawn,backing,bail,hostage,assurance,gage,earnest

adjective

additional but subordinate; secondary.

the collateral meanings of a word